JP3126464B2 - Image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recording an image on a surface of a photoreceptor by uniformly charging the surface of the photoreceptor by contacting the surface of the photoreceptor with a charged conductive magnetic toner. The present invention relates to an image forming method for forming an image on a material.

[0002]

2. Description of the Related Art An electrophotographic process using a charger for uniformly charging the entire surface of a photoreceptor by corona discharge is well known. In such an electrophotographic process, an electrostatic latent image is formed on a uniformly charged photoconductor surface by exposure according to recorded information. Next, a conductive magnetic toner charged to the opposite polarity is brought into contact with the electrostatic latent image on the photoreceptor to form a toner image.

More specifically, the conductive magnetic toner is brought into contact with a non-magnetic conductive sleeve having a built-in magnet roller at an end of the developing device, and an image portion (hereinafter referred to as an "image portion") on the photosensitive member on which an electrostatic latent image is formed. Electric charges are injected by an electric field acting between the non-exposed portion) and the conductive sleeve. Subsequently, the charged conductive magnetic toner is conveyed while being held by the conductive sleeve with the rotation of the magnet roller, and adheres to the electrostatic latent image in the image area to form a toner image.

However, in the system having such a configuration, the charging potential of the photoconductor must be sufficiently high in order to sufficiently inject the electric charge into the conductive magnetic toner. For this purpose, a charger that performs corona discharge is used, but corona discharge generates ozone, which causes deterioration of the charger, the surface of the photoconductor, and the like.

Further, in the above system, since the non-exposed portion is an image portion, the efficiency is extremely low for an image forming apparatus such as a printer for writing characters and the like.

For example, Japanese Patent Publication No. 2-4900 discloses a conductive magnetic material which is transferred by a magnet roller via a conductive sleeve to a photosensitive member having a transparent support, a transparent electrode, and a photoconductive layer. The photoconductor is charged by charging the toner and bringing the charged conductive magnetic toner into contact with the surface of the photoconductive layer, and then performing exposure in accordance with the recorded information from the transparent support side to form a toner image on the photoconductor surface. Has been proposed.

According to this image forming method, a charger and a cleaning mechanism are not required, the configuration of the image forming apparatus can be reduced in size and simplified, and the life of the photosensitive member can be extended.

[0008]

However, in the above-described conventional configuration, the photoconductor is neutralized after the toner image is transferred to the recording paper, but when a trouble such as a paper jam occurs, the inside of the image forming apparatus is lost. When the surface is opened, the surface potential of the photoconductor may become uneven due to strong external light.
In such a case, it takes time for the surface potential of the photoconductor to become substantially the same as that of the conductive magnetic toner as compared with the continuous operation, so that the characteristics of the photoconductor are completely recovered when the exposure process is performed. May not be.

Another problem is that toner drops due to abrupt acceleration at the start of operation of a rotating portion such as a photoreceptor and the like, and the reproducibility of gradation is deteriorated in image formation immediately after the start of operation.

As a result, the above-described conventional image forming method has a problem that a stable image quality is not always obtained immediately after the start of operation in any case.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method capable of improving initial image forming characteristics and constantly obtaining a stable image quality from an initial copied image in view of the above problems.

[0012]

According to a first aspect of the present invention, there is provided an image forming method comprising: a photosensitive member having a transparent support, a transparent electrode, and a photoconductive layer provided in order; The toner carrier (for example, the photosensitive drum)
(Developing sleeve) charges the conductive magnetic toner conveyed, contacts the charged conductive magnetic toner to the surface of the photoconductive layer, and performs exposure according to the recorded information from the transparent support side, so that the surface of the photoconductor is exposed. In the image forming method for forming a toner image, the photosensitive member surface is rotated at least once while applying a voltage to the toner carrier, and then the exposure is performed and the photosensitive member surface is rotated at least once .
Sometimes, the surface of the photoconductor is rubbed against the conductive magnetic toner.
Increasing the overspeed gradually (for example, turning the main motor
Rolling speed is gradually increased) .

[0013]

According to a second aspect of the present invention, there is provided an image forming method comprising: a transparent support; a transparent electrode;
And a photoconductor provided with a photoconductive layer and a toner carrier
Charges the conductive magnetic toner conveyed by the
The conductive magnetic toner contacts the surface of the photoconductive layer,
By performing exposure according to the recorded information from the bright support side
To form a toner image on the photoreceptor surface.
While applying a voltage to the toner carrier
After at least one round of the body surface,
To disturbances when to at least one cycle of the photosensitive member surface, to rotate the alternating magnetic field inside the toner carrying member by (e.g., to rotate the magnetic roller), a conductive magnetic toner in contact with the surface of the photoconductive layer It is characterized by having

According to a third aspect of the present invention, there is provided an image forming method, comprising: a transparent support; a transparent electrode;
And a photoconductor provided with a photoconductive layer and a toner carrier
Charges the conductive magnetic toner conveyed by the
The conductive magnetic toner contacts the surface of the photoconductive layer,
By performing exposure according to the recorded information from the bright support side
To form a toner image on the photoreceptor surface.
While applying a voltage to the toner carrier
After at least one round of the body surface,
The method further comprises rotating the non-magnetic and conductive sleeve provided on the surface of the toner carrier when the surface of the photoconductor is rotated at least once to increase the amount of the conductive magnetic toner transported to the exposure position. And

[0016]

According to the constitution of the present invention, the conductive magnetic toner is provided.
The rubbing speed of the photoreceptor surface against
To start the rotation of the photoconductor and the conveyance of the conductive magnetic toner.
The resulting rapid acceleration may cause toner drop
And the most efficient charging of the photoreceptor surface
As well as prevent out-of-step.
You.

[0017]

[0018]

Since the voltage applied to the toner carrier is low, even if the photoconductor is charged while the rotation speed of the photoconductor is low, the photoconductor is not damaged unlike the corona discharge.

According to the second aspect of the present invention, by rotating the alternating magnetic field inside the toner carrier, the conductive magnetic toner in contact with the surface of the photoconductive layer is disturbed. The surface of the photoconductor can be charged more efficiently.

According to the third aspect of the present invention, the non-magnetic and conductive sleeve provided on the surface of the toner carrier is rotated,
Since the transport amount of the conductive magnetic toner to the exposure position is increased, the surface of the photoconductor can be charged more efficiently than the case where only the photoconductor is cycled.

[0022]

1 to 13 show an embodiment of the present invention.
The description will be made based on the following.

As shown in FIG. 8, the image forming apparatus for carrying out the image forming method according to the present invention includes a cylindrical photosensitive drum 1 which is rotatably supported in the direction of arrow A in the figure. I have.

As shown in FIG. 11, the photosensitive drum 1 has a transparent support 1a, a transparent electrode 1b, and a photoconductive layer 1a.
c has a three-layer structure in which layers are sequentially stacked. The transparent support 1a is formed in a cylindrical shape using an optically transparent substance. The transparent electrode 1b is made of a transparent conductive film such as In ₂ O ₃ or SnO ₂ sputtered on the surface of the transparent support 1a. The photoconductive layer 1c is made of a photoconductive material such as Se, ZnO, CdS, or amorphous Si. In this embodiment, the transparent electrode 1b has an In thickness of 0.5 μm.
_{A 2} O ₃ layer and a 3 μm-thick amorphous Si layer were formed as the photoconductive layer 1c.

As shown in FIG. 8 again, inside the photosensitive drum 1, there is provided an exposure device 7 having an LED array in which a short focus lens array is combined with a light emitting diode array. The exposure device 7 emits light in accordance with a video signal generated from character data or image data to be recorded, and the emitted light passes through the transparent support 1a and the transparent electrode 1b. Light is condensed on a predetermined circumference of the conductive layer 1c.

The developing device 2 is provided near the photosensitive drum 1 and near the exposure position, and has a developing tank 3 for storing a conductive toner T as a developer, and a conductive toner T in the developing tank 3. Roller 4 for stirring the toner, and the opening 3 of the developing tank 3
a, a developing sleeve 5b provided along the longitudinal direction of the photosensitive drum 1. Developing sleeve 5b
Is made of a non-magnetic conductive member such as aluminum or martensitic stainless steel. Further, in the developing sleeve 5b, a magnetic roller 5a in which N-polarity and S-polarity magnets are alternately arranged is rotatably inserted in a direction indicated by an arrow B in the drawing.

Thus, while the conductive toner T is held on the surface of the developing sleeve 5b by the alternating magnetic field generated by the rotation of the magnetic roller 5a in the B direction, the conductive toner T is kept in the B direction, which is the rotation direction of the magnetic roller 5a. It is transported in the reverse direction B ′ (see FIG. 11).

As shown in FIG. 11, the developing sleeve 5b is arranged at a position where the magnetic brush formed on the surface of the developing sleeve 5b by the magnetic roller 5a contacts the surface of the photoconductive layer 1c. It is provided rotatable in the direction of arrow C shown in FIG. In addition, a doctor blade 6 is provided near the opening 3a for adjusting the transport amount of the conductive toner T to the exposure position to a predetermined amount.

Here, an example of a configuration for rotatably supporting the developing sleeve 5b will be described. As shown in FIG. 7, both ends of the developing sleeve 5b are formed in a shaft shape, and are rotatably supported by bearings 33 provided in each of the opposite walls of the developing tank 3. However, one end of the developing sleeve 5b penetrates the developing tank 3 via the bearing 33, and is a driven end to which the developing sleeve driving gear 31 is fixed.
The driven end of the magnetic roller 5a loosely inserted into the developing sleeve 5b is also formed in a shaft shape and penetrates the end surface of the developing sleeve 5b, and a magnetic roller driving gear 32 is fixedly provided.

The conductive toner T is kneaded with, for example, a resin made of a styrene-acryl copolymer or the like, and magnetic powder such as iron powder or ferrite, carbon black, or the like, and then pulverized, and classified into several μm to several tens μm. Powder can be used.

On the other hand, as shown in FIG.
The transfer / fixing belt 8 in the form of an endless belt is formed on the upper surface of a transfer roller 9 provided above the photosensitive drum 1.
Is pressed. The transfer / fixing belt 8 includes a heating device 10 for fixing the conductive toner T transferred from the photosensitive drum 1 to the surface of the transfer paper P, and a tension roller 11 disposed on the lower left side of the heating device 10. Has been passed over. Note that a pressure roller 12 is provided above the heating device 10.
Are arranged close to each other.

The transfer / fixing belt 8 is formed of a film material mainly composed of a polyimide resin having excellent mechanical strength and high heat resistance. However, the material is not limited to this, and it is sufficient that the surface to which the conductive toner T is transferred has at least an insulating property as described later. For example, an electroformed nickel belt as a base material Or the like, which is obtained by applying a fluorine coating to a metal belt such as a metal belt. Further, the surface may be roughened so that the gloss of the image becomes appropriate. The thickness of the transfer / fixing belt 8 is preferably about 10 to 200 μm in consideration of thermal conductivity and mechanical strength.

The heating device 10 heats and melts the conductive toner T transferred to the surface of the transfer / fixing belt 8 as described later. This heating is performed by a planar heating element 10 a provided so as to directly contact the surface of the transfer / fixing belt 8 on the upper surface of the heating device 10. The heating element 10a is configured by a ceramic heater in which a planar Mo-based heating resistor is printed on an alumina ceramic substrate, and a glass coat is printed and laminated thereon.

Further, as shown in FIG. 9, the image forming apparatus of this embodiment has a main motor 13 which is a driving source of the apparatus.
A recording material transport unit 14 that transports the transfer paper P to the heating device 10; and a paper output unit 21 that discharges the transfer paper P from inside the device.
Are provided. In this embodiment, a stepping motor is used as the main motor 13.

In the recording material transport section 14, a paper input opening (not shown) formed in the apparatus main body is connected to a transfer material supply section (not shown). In addition, in order from the vicinity of the opening in the apparatus, a paper input detection switch (not shown) is turned ON / O.
Paper feed actuator 16 for FF, a pair of paper feed rollers 1
8 and a paper supply solenoid 20 are provided above the developing tank 3, and a pair of registration rollers 19 and a conveyance guide plate 15 are provided on a conveyance path leading to the heating device 10.

The paper feed solenoid 20 controls the rotation of the registration roller 19 in order to control the timing at which the toner image on the transfer / fixing belt 8 and the transferred transfer paper P reach the position of the heating element 10a. Control, that is, ON / OF connection between a registration roller 19 and a rotation transmission system (not shown) for transmitting the driving force of the main motor 13 to each rotation unit.
F.

On the other hand, in the paper output section 21, between the heating device 10 and a paper output opening (not shown) formed in the apparatus main body, a paper output detection switch (not shown) is turned ON / OF.
A paper ejection actuator 23 that performs F, a paper ejection guide plate 22 that guides paper ejection, and a pair of paper ejection rollers 25 are sequentially provided.

The transfer / fixing belt 8 and the heating device 1
0 and the photosensitive drum 1 may be provided in the apparatus as an integrated unit.

Next, a control system for implementing the image forming method according to the present invention will be described with reference to FIG.

In the control system of the present invention, the printer engine control CPU 54, the ROM / RAM unit 53,
The controller interface 52, the driver group 55, the input interface 56, and the buffer / LED driver unit 57 are connected to each other via each data bus or address bus. The controller interface 52 has a control CPU 51 via a bus.
Is connected.

The driver group 55 includes a main motor 13 driven by a dedicated driver, a sheet feeding solenoid 20, and a solid-state relay for fixing.
y) Drive group such as 61 is connected. The input interface 56 includes a paper feed sensor 62 and a paper output sensor 6.
3. Various detectors such as a fixing temperature sensor 64 and a toner sensor 65 are connected. Furthermore, the buffer /
The LED driver 58 is connected to an LED head 58 on which the above-mentioned LED array is arranged.

The control CPU 51 creates a bit map for at least one page in the RAM area of the ROM / RAM unit 53 via the controller interface 52 based on the print / image information input from the external device. When receiving the printout instruction, the control CPU 51 outputs a print start signal to the printer engine control CPU 54.

Printer engine control CPU 54
Supplies a video signal (a switching signal including a synchronizing signal) according to the bit map to the buffer / LED driver unit 57, and controls the output timing of the buffer / LED driver unit 57 while controlling the output timing of the LED head 58. Blink the beam. The printer engine control CPU 54 sends a command corresponding to each image forming process or image forming condition to the ROM / RAM based on various detection signals received from the input interface 56.
A signal is generated according to the control program stored in the ROM area of the unit 53 and activates the driver group 55.

The paper feed sensor 62 includes the above-described paper input detection switch, and is constituted by a sensor group for detecting the presence or absence and size of the transfer paper P in the transfer material supply unit, a paper jam, or the like. The paper output sensor 63 includes the above-described paper output detection switch, and is configured by a sensor group that detects whether or not the transfer paper P has been discharged without paper jam. The fixing solid state relay 61 turns ON / OFF the energization of the heating element 10a based on the temperature detected by the fixing temperature sensor 64. Thereby, the temperature of the heating element 10a is controlled to an optimum value. The toner sensor 65 detects the amount of toner in the developer, the amount of developed toner on the photoconductor, and the like. As a result, toner is supplied, and the image density is stabilized.

The operation of the above-described control system for the image forming apparatus in the above configuration will be described below. Note that a series of control operations are performed in synchronization with the clock pulse signal shown in FIG.

When one sheet of transfer paper P is fed into the apparatus from the transfer material supply unit through the paper input opening, the leading end of the transfer paper P pushes up the paper feed actuator 16. When the paper input detection switch outputs a transfer paper P supply detection signal, the main motor 13 is turned on by the printer engine control CPU.
The rotation is started based on the command of 54.

The rotation of the main motor 13 is controlled by the feed roller 1
The transfer paper P is conveyed to the registration roller 19 along the upper surface of the developing tank 3 with the rotation of the paper feed roller 18. On the other hand, since the connection between the registration roller 19 and the drive shaft is turned off by the paper feeding solenoid 20, the registration roller 19 is not rotating. For this reason,
The leading end of the transfer paper P reaches the registration roller 19 and stops. Since the frictional resistance of the surface of the paper feed roller 18 is small, when the transfer paper P stops in this manner,
Keeps slipping on the surface of the transfer paper P.

When this state is detected by the paper feed sensor 62,
As shown in step 1 (hereinafter referred to as S1) in the flowchart of FIG. 1, the printer engine control CPU 54 enters a standby state for receiving a print start signal output by the control CPU 51. here,
If the print start signal is not generated within the predetermined time, the printer engine control CPU 54
The rotation of No. 3 is temporarily stopped.

When a print start signal is generated in the standby state,
The printer engine control CPU 54 is configured as shown in FIG.
(B) As shown in (c), the output of the paper feed sensor 62 is detected at the rise of the print start signal (S2). Subsequently, the printer engine control CPU 54 outputs a drive start command to the dedicated driver of the main motor 13 (S
3) together with the main motor 1 via the dedicated driver
3 is gradually increased (S4). For example, as shown in the period t ₁ in FIG. 2 (d), while the photosensitive drum 1 is at least one revolution, gradually increasing the frequency of the drive pulses supplied to the main motor 13.

As a result, the rotation of the main motor 13 is transmitted to all the rotating parts except the registration roller 19 via the rotation transmitting system, and the photosensitive drum 1 and the magnetic roller 5 are rotated.
a and the rotation speed of the developing sleeve 5b gradually increases.

FIGS. 11 to 13 show the reason why the rotation speed of the main motor 13 is gradually increased.
The mechanism of image formation will be described based on FIG.

First, due to the alternating magnetic field generated by the rotation of the magnetic roller 5a in the direction B, the conductive toner T stored in the developing tank 3 causes the magnetic brush on the surface of the developing sleeve 5b as shown in FIG. While forming, the photosensitive drum 1
Are transported in the direction B ', which is the direction opposite to the direction A, which is the direction of rotation of. At this time, at the contact portion between the magnetic brush and the photosensitive drum 1, the potential difference of several tens of volts applied between the developing sleeve 5b and the transparent conductive layer 1b causes the photosensitive toner T to be exposed from the developing sleeve 5b. The electric charge is injected into the body drum 1. Thus, the surface of the photosensitive drum 1 is charged to substantially the same potential as the developing sleeve 5b.

However, it may take some time before the surface of the photosensitive drum 1 is charged to substantially the same potential as the developing sleeve 5b at the start of the operation as compared with the continuous operation of image formation. Further, when the apparatus is stopped, the photosensitive drum 1 and the transfer / fixing belt 8 are in pressure contact with each other. At this time, the characteristics of the photosensitive drum 1 are uneven due to the stress applied to the photosensitive drum 1. It is possible that it will occur. Therefore, as described above, after the print start signal is generated, while the photosensitive drum 1 rotates at least one rotation,
The rotation speed of the main motor 13 is sequentially increased to uniformly charge the photosensitive drum 1 and sufficiently recover its characteristics.

A toner reservoir is formed on the downstream side of the rotation of the photosensitive drum 1 at the contact portion between the magnetic brush and the photosensitive drum 1, but when the rotation of the photosensitive drum 1 and the developing sleeve 5b is started, The occurrence of toner drop due to the accompanying rapid acceleration or vibration is also not preferable for the charging efficiency of the photosensitive drum 1 and the reproducibility of gradation.
Therefore, gradually increasing the rotation speed of the main motor 13 also has the effect of preventing toner from falling out of the toner pool, improving the charging efficiency, and further stabilizing the image quality immediately after the start of operation.

The conductive toner T contacted with the photosensitive drum 1 as described above causes the magnetic force generated by the magnetic roller 5a to be generated when the surface of the photosensitive drum 1 and the developing sleeve 5b become equipotential. Since it is dominantly applied, it does not adhere to the photosensitive drum 1.

Next, as shown in FIG. 12, immediately before the photosensitive drum 1 and the conductive toner T separate from each other on the downstream side of the rotation of the photosensitive drum 1, or at a portion C in the vicinity thereof, the exposure device 7 When the LEDs corresponding to the image patterns to be recorded are sequentially selected and exposed, the photoconductive layer 1c and the transparent electrode 1b at the portion C have substantially the same potential. That is,
The potential on the surface of the photosensitive drum 1 at the portion C decreases, and a potential difference is generated between the portion C and the developing sleeve 5b.

As a result, the electrostatic force acting between the developing sleeve 5b and the surface of the portion C of the photosensitive drum 1, the van der Waals force acting between the conductive toner T and the photosensitive drum 1, and the like are changed by the magnetic roller. Since the magnetic force generated by 5a is overcome, the conductive toner T remains on the surface of the portion C. Thus,
A toner image corresponding to the image pattern is formed on the surface of the photosensitive drum 1.

After the frequency of the drive pulse supplied to the main motor 13 is gradually increased as described above, it is determined in S5 whether the rotation speed of the main motor 13 has reached a predetermined value. This determination may be made based on whether the frequency of the drive pulse has reached a predetermined value,
It may be made based on whether a predetermined time t ₁ has elapsed. In any case, with the rotation speed of the main motor 13 equal to the normal printing speed, in S6,
The printer engine control CPU 54 has a ROM /
A request signal for transferring the print data stored in the RAM area of the RAM unit 53 to the buffer area of the buffer / LED driver unit 57 is output.

At S7, when it is confirmed that the output level of the print data supplied from the buffer area to the LED driver is stable, at S8, the LED driver drives the LED corresponding to the print data, and Exposure 1 is performed.

As described with reference to FIGS. 11 to 13, the toner image developed on the surface of the photosensitive drum 1 is
When a voltage having a polarity opposite to that of the injected charge of the toner image is applied to the transfer roller 9, the dielectric belt 8 is pressed at the pressure contact portion between the photosensitive drum 1 and the transfer roller 9 via the dielectric belt 8.
Is transferred to the surface of

Next, at the timing when the leading end of the toner image on the dielectric belt 8 and the leading end of the transfer paper P reach the pressure contact portion between the dielectric belt 8 and the pressure roller 12 on the heating device 10 at the same time. , Printer engine control CPU 54
Outputs a signal shown in FIG. 2G to the registration solenoid 20. Accordingly, the rotation of the main motor 13 is transmitted to the above-described registration roller 19, and the transfer paper P is transported to the heating device 10.

As a result of the dielectric belt 8 and the transfer paper P being conveyed while being superposed between the heating device 10 and the pressure roller 12, the transfer and fixing of the toner image onto the transfer paper P are performed simultaneously. . The releasability of the surface of the dielectric belt 8 from the conductive toner T melted by heating is better than that of the transfer paper P.

Thereafter, the transfer paper P on which the toner image has been transferred and fixed is pushed up by the paper output detection actuator 23, and is discharged out of the apparatus through the paper output opening by the rotation of the paper output roller 25. The transfer paper P is output in S9 of FIG. 1 and in FIG.
As shown in (h), it is detected by a paper output sensor 63 including a paper output detection switch linked to the paper output detection actuator 23. When a paper jam occurs, predetermined processing such as an error display is performed in S10.

Finally, at S11, the printer engine control CPU 54 sets the heating device 10 after a predetermined time period in which the paper-in detection signal from the paper-in detection switch and the paper-out detection signal from the paper-out detection switch are not detected. Of the heating resistor 10a and the driving of the stepping motor 13 are terminated.

Hereinafter, the effects of the image forming method according to the present invention will be specifically described.

FIGS. 3 to 6 show the change over time of the surface potential of the photosensitive drum 1 with the time point at which the drive of the main motor 13 is started at the same time when the voltage is applied to the developing sleeve 5b taken as 0. In this measurement, the diameter of the photosensitive drum 1 was 30 mm, and the peripheral speed of the photosensitive drum 1 during printing was 23.
The operation was carried out under the conditions that the apparatus cover was opened before operation and the photosensitive drum 1 was exposed to room light of about 1000 lux before the operation.

However, in the measurement of FIGS. 3 to 5, the photosensitive drum 1 was rotated at a peripheral speed of 23.6 mm / sec from the beginning, whereas in the measurement of FIG. During one rotation, the peripheral speed was gradually increased from 0 to finally reach 23.6 mm / sec.

At the same time as the voltage is applied to the developing sleeve 5b, the driving of the main motor 13 is started, the photosensitive drum 1 is first rotated once at a peripheral speed of 23.6 mm / sec, and then the printing is performed while rotating the magnetic roller 5a. When the process was started, the surface potential of the photosensitive drum 1 changed as shown in FIG. That is, FIG. 3 shows that the surface potential gradually increased during four seconds when one rotation of the photosensitive drum 1 was completed.

Next, at the same time as rotating the photosensitive drum 1 at a constant speed, the magnetic roller 5a is also rotated at a constant speed to rotate the alternating magnetic field, so that the conductive magnetic toner contacting the surface of the photoconductive layer 1c is removed. When disturbed, as shown in FIG.
It can be seen that the rise of the surface potential is earlier than in FIG. However, also in this case, the surface potential did not become sufficiently high until one rotation of the photosensitive drum 1 was completed.

Further, the photosensitive drum 1 and the magnetic roller 5a
And the developing sleeve 5b are simultaneously rotated at a constant speed to increase the transport amount of the conductive magnetic toner to the contact portion between the surface of the photosensitive drum 1 and the magnetic brush, as shown in FIGS. It can be seen that the rise of the surface potential is faster than that of No. 4.

Finally, when the photosensitive drum 1, the magnetic roller 5 a and the developing sleeve 5 b are simultaneously rotated while gradually increasing the rotation speed of the main motor 13 to charge the photosensitive drum 1, The surface potential changed as shown in FIG. That is, it can be understood that the surface potential rises fastest and the photosensitive drum 1 is most efficiently charged.

As described above, while the voltage is applied to the conductive toner T, the surface of the photosensitive drum 1 is rubbed against the conductive toner T prior to the formation of the toner image. Can be made uniform, so that a toner image of stable image quality can be obtained from the start of the operation.

More preferably, by gradually increasing the rotation speed of the main motor 13 and gradually increasing the rubbing speed between the surface of the photosensitive drum 1 and the conductive toner T, the charging efficiency is further improved. Can also prevent the toner from dropping due to the shock. Increasing the rotation speed of the main motor 13 gradually is also advantageous in preventing so-called step-out.

In the conventional image forming method, if the rotation speed of the main motor is set lower than usual at the start of the operation, overexposure and overcharging are caused, so that preferable results cannot be obtained.

[0075]

According to the first aspect of the present invention, there is provided an image forming method comprising:
As described above, after at least one round of the photoconductor surface while applying a voltage to the toner carrier, exposure is performed ,
When the photoreceptor surface is rotated at least once, conductive
Slowly increase the rubbing speed of the photoconductor surface against the magnetic toner
It is a Kusuru configuration.

[0076]

[0077]

Therefore, it is possible to prevent the toner from dropping due to the sudden acceleration caused by the start of the rotation of the photoconductor and the start of the conveyance of the conductive magnetic toner, and the charging of the surface of the photoconductor can be performed most efficiently. At the same time, there is an effect that so-called step-out can be prevented.

[0079] The image forming method according to the invention of claim 2 is, as described above, the photosensitive member while applying a voltage to the toner carrier
After making at least one round of the surface, perform exposure and
When the photosensitive member surface is rotated at least once, the alternating magnetic field is rotated inside the toner carrier to disturb the conductive magnetic toner contacting the surface of the photoconductive layer.

Therefore, an effect is obtained that the surface of the photoconductor can be more efficiently charged before the formation of the toner image, as compared with the case where only the photoconductor is cycled.

According to a third aspect of the present invention, as described above, the photosensitive member is applied while applying a voltage to the toner carrier.
After making at least one round of the surface, perform exposure and
When the photosensitive member surface is rotated at least once, the non-magnetic and conductive sleeve forming the surface of the toner carrier is rotated to increase the amount of conductive magnetic toner transported to the exposure position.

Therefore, it is possible to more efficiently charge the surface of the photosensitive member prior to the formation of the toner image, as compared with the case where only the photosensitive member makes one cycle.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control operation by an image control method according to the present invention.

FIG. 2 is a timing chart showing a temporal relationship between various signal outputs accompanying the control operation.

FIG. 3 is a graph showing a time change of a surface potential of the photosensitive drum when the photosensitive drum is charged by rotating only the photosensitive drum at a constant speed.

FIG. 4 is a graph showing a change over time of the surface potential of the photosensitive drum when the photosensitive drum and the magnetic roller are rotated at a constant speed to charge the photosensitive drum.

FIG. 5 is a graph showing a time change of the surface potential of the photosensitive drum when the photosensitive drum, the magnetic roller, and the developing sleeve are each rotated at a constant speed to charge the photosensitive drum.

FIG. 6 is a graph showing a change over time of the surface potential of the photosensitive drum when the photosensitive drum is charged by gradually increasing the rotation speed of the main motor.

FIG. 7 is a side view having a partial cross section showing an example of a configuration for rotatably supporting a developing sleeve.

FIG. 8 is a longitudinal sectional view illustrating a main configuration of an image forming apparatus that performs an image control method according to the present invention.

FIG. 9 is a configuration diagram schematically showing various components of the image forming apparatus.

FIG. 10 is a block diagram illustrating a configuration of a control system that executes the control operation.

FIG. 11 is an explanatory view conceptually showing a state where the surface of the photosensitive drum is charged by contact with a conductive toner.

FIG. 12 is an explanatory view conceptually showing a state where an electrostatic latent image is formed on the surface of the photosensitive drum.

FIG. 13 is an explanatory diagram conceptually showing a state in which the electrostatic latent image is developed with conductive toner.

[Explanation of symbols]

 Reference Signs List 1 photoconductor drum (photoconductor) 1a transparent support 1b transparent electrode 1c photoconductive layer 5b developing sleeve (toner carrier and sleeve) T conductive toner

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/05 B41J 2/44

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein a conductive magnetic toner carried by a toner carrier is charged on a photoreceptor provided with a transparent support, a transparent electrode, and a photoconductive layer in that order. In an image forming method of forming a toner image on the surface of a photoconductor by performing exposure according to recorded information from the transparent support side while contacting the surface, the surface of the photoconductor is applied while applying a voltage to the toner carrier. after at least one cycle, it performs the exposure, the top
When the photosensitive member surface is rotated at least once,
Gradually increase the rubbing speed of the photoreceptor surface against
Image forming method characterized by Kikusuru. 2. A method according to claim 1, wherein the conductive magnetic toner carried by the toner carrier is charged on a photosensitive member provided with a transparent support, a transparent electrode, and a photoconductive layer. In an image forming method of forming a toner image on the surface of a photoconductor by performing exposure according to recorded information from the transparent support side while contacting the surface, the surface of the photoconductor is applied while applying a voltage to the toner carrier. after at least one cycle, it performs the exposure, when to at least one cycle of the photoreceptor surface, the toner charge of
By rotating the alternating magnetic field inside the carrier, the photoconductive layer
An image forming method comprising disturbing a conductive magnetic toner that contacts a surface of a toner . 3. A photoconductor provided with a transparent support, a transparent electrode, and a photoconductive layer is charged with a conductive magnetic toner carried by a toner carrier, and the charged conductive magnetic toner is charged on the photoconductive layer. In an image forming method of forming a toner image on the surface of a photoconductor by performing exposure according to recorded information from the transparent support side while contacting the surface, the surface of the photoconductor is applied while applying a voltage to the toner carrier. after at least one cycle, it performs the exposure, when to at least one cycle of the photoreceptor surface, the toner charge of
Rotates the non-magnetic and conductive sleeve that forms the surface of the carrier
To increase the amount of conductive magnetic toner transported to the exposure position.
An image forming method characterized by increasing the size.